Here is the full list of all 39 Blacksad: Under the Skin achievements.
Complete the Baseball sheet of the Hall of Fame album.
Complete the Hall of Fame album.
Complete the Football sheet of the Hall of Fame album.
Complete the Boxing sheet of the Hall of Fame album.
Complete the Hockey sheet of the Hall of Fame album.
Watch all 6 alternate scenes at the end of the game.
Complete the game without dying a single time.
Contribute to as many deaths as possible.
Complete all deductions in the game.
Help the Colberts live a second honeymoon and receive their gratitude.
Buy your favorite goat a second burger.
Stand up to Sam as many times as you can.
Take 400 nightstick blows. Maybe a few less.
Get hired twice for the same case.
Do not take the case.
Find all false endings in the game.
Complete the game dying less than 9 times.
Now for real.
Solve the case.
Take your sixth beating.
Do not scare Brunhilda while telling her a story.
Beat someone up for once.
Play baseball.
Complete Blacksad's silence conveniently.
Play bad cop convincingly.
Play good cop convincingly.
Take your fifth beating.
Interact with as many books as you can.
Why's that poster in Dunn's flat?
Put your acting skills to the test.
Stand up to Quince as many times as you can.
Take your fourth beating.
Charm Helen Moore into giving you a present.
Buy a box of cigarettes from the nursing staff.
Take your third beating.
Take a ride with the city's most honest bookmarker.
Take your second beating.
Find your most valuable tool.
Take your first beating (spoiler: it won't be the last!).